There is an ever-increasing demand for smaller and smaller electronic devices in today's high-tech marketplace. As a result, new and innovative. fabrication techniques have become a focal point of many manufacturers. Many manufacturers have turned to laser processing as a means of fabrication, (e.g. for blowing fuses, via and hole drilling, ablation or material transformation patterning, or resistor trimming). However, most laser processing systems are very costly and inefficient. For example, single feature laser processing systems process one feature (i.e. pattern, hole or via) through ablative, additive, or transformational means at a time and are therefore incapable of efficiently operating in large volume manufacturing environments. Many manufacturers have sought means to reduce cost by increasing yield. However, increasing yield often requires higher optical power from the laser. Increasing optical power reduces the processing time each feature thus yield is increased, but this increase in optical power often has a negative effect of lowering the quality in the fabricated devices due to overexposure. Therefore there exists a need to reduce cost by increasing manufacturing yield without sacrificing manufacturing quality. Likewise, there exists a need to increase manufacturing quality without sacrificing manufacturing yield.
One way that manufacturers have sought to increase manufacturing yield and reduce cost is through parallel processing, where a energy beam is split in order to process more than one feature at a time. Diffractive optical elements (DOEs) are often employed in parallel laser processing systems because they are capable of providing highly efficient and highly uniform beam splitting. Unlike conventional optical components that utilize refraction and/or reflection, DOEs enable parallel processing by optically diffracting and directly controlling the optical phases of the beam. Therefore, a wide range of applications including, for example, multi-spot beam splitters or shapers, can be expected. The beam splitting or shaping can be used for drilling holes or vias of various sizes and shapes and multiple ablation or material transformation patterns.
A method of patterning holes in a surface of an object through the use of parallel processing with a DOE can be found in U.S. Pat. No. 6,635,849, entitled “Laser beam machine for micro-hole machining.” The '849 patent details a process of beam splitting to increase manufacturing yield. To ensure that manufacturing quality is also met, the '849 patent details a process where masks control the optical power and the beam diameter from over-exposing the object under process. However, masks (e.g. aperture, imaging or pinhole masks allow only a small portion of the laser's beam to be used, wasting 20% to 80% of the optical power. Thus, the highest potential yield is not realized and manufacturing cost is increased. Therefore there exists a need to more economically use the optical power supplied by laser processing systems.
It is an object of the invention to reduce cost by increasing manufacturing yield without sacrificing manufacturing quality.
It is another object of this invention to increase manufacturing quality without sacrificing manufacturing yield.
It is yet another object of this invention to more economically use the optical power supplied by laser processing systems.